(a) Field of the Invention
The present invention relates generally to a saw blade adjusting device of a band sawing machine, more particularly to a saw blade adjusting device in which the rotary motion of an urging knob is translated into an axial urging motion to cause abutment or separation of the urging knob and an urging seat to thereby facilitate adjustment and replacement of the saw blade and maintain the distance between upper and lower wheel frames of the band sawing machine.
(b) Description of the Prior Art
Band sawing machines are widely used in cutting operations because they are easy to operate. FIG. 1 shows a saw blade adjusting structure of a conventional band sawing machine. As shown, a screw rod 2 is rotated to cause a saw blade wheel 3 to displace to allow adjustment of the distance between upward and downward displacement thereof, whereby mounting or disengagement of a saw blade 4, as well as adjustment of the tautness of the saw blade 4 can be achieved. If the tautness of the saw blade 4 is not sufficient, the cutting operation cannot proceed properly. Conversely, if the saw blade 4 is excessively taut, it may easily break. As the conventional saw blade adjusting structure only utilizes a spring 5 to fit onto the screw rod 2, without any linking-up elements to achieve urging and tightening effects, it may easily become loosened during violent cutting operation of the band sawing machine. Violent vibration may cause the distance between upper and lower wheel frames 3 and the tautness of the saw blade 4 to alter, which will severely affect the cutting efficiency of the machine. Improvements thereon are therefore necessary.